This invention concerns an administration set of the type used for dispensing parenteral liquid to a patient, and, more particularly, to an administration set including a burette having a pivotable air valve.
Administration sets including burettes with drip chambers are widely used for administering parenteral liquids to a patient. The burettes typically include a burette chamber with a primary liquid inlet to the chamber and also an injection site communicating with the chamber for injecting medicament into the chamber so that, for example, the medicament may be diluted with the primary liquid.
When the burette is being filled with liquid or medicament is being injected into the burette for dilution with the liquid, communication of the burette chamber with the air outside the chamber is necessary. To this end, in one prior art administration set construction, an air tube communicates with the burette chamber, with the air tube having a filter at one end and a clamp between the filter and the burette chamber. When it is desired for burette chamber to be open to air, the clamp is opened.
In another prior art construction, as disclosed in McPhee U.S. Pat. No. 3,776,229, a rotatable air valve communicates with the burette chamber for providing the necessary air vent. However, the rotary air valve disclosed in this patent has certain disadvantages. For example, because of the grooved construction of the system, the rotatable portion of the air valve can be easily pulled off by an operator. Additionally, it has been found that the air valve disclosed in this patent generally requires silicone lubricant in order to provide adequate sealing properties when the valve is closed. This is disadvantageous because the silicone lubricant may become introduced into the burette. Further, the filter carried within the air valve may become clogged, particularly when the unit is shaken by the operator, and there is no way to unclog the filter once it becomes clogged.
Accordingly, it is an object of the present invention to provide an administration set having a burette which obviates the requirement for an air tube extending from the burette chamber with a clamp between the air filter and the burette chamber.
Another object of the present invention is to provide an administration set with a burette having a pivotable air valve of the type that cannot be easily removed by an operator.
A further object of the present invention is to provide an administration set having a burette which uses an air valve that does not require silicone lubrication.
A still further object of the present invention is to provide an administration set having an air valve which is structurally arranged to allow an operator to at least partially unclog the filter carried by the air valve, if the filter should become clogged.
Other objects and advantages of the present invention will become apparent as the description proceeds.